Bush backs off key Iran claim

United States President George W Bush says he is unsure whether top Iranian leaders are behind arms shipments to anti-US fighters in Iraq, undercutting a volatile US charge levelled just days ago.

But he says there is no doubt the elite Al-Qods Force of the Iranian Revolutionary Guards Corps is behind powerful new improvised explosive devices (IEDS) killing US soldiers in Iraq.

And Mr Bush has vowed to "do something about it."

"Whether (Iranian President Mahmoud) Ahmadinejad ordered the Qods Force to do this, I don't think we know. But we do know that they're there," Mr Bush told his first press conference since December 20.

Three days earlier, unnamed US officials in Baghdad told a roomful of reporters "the senior levels of the Iranian Government" had approved weapons shipments to Iraqi fighters.

But Mr Bush said he could not vouch for it.

"I can say with certainty that the Qods Force, a part of the Iranian Government, has provided these sophisticated IEDs [improvised explosive devices] that have harmed our troops," he said.

"I do not know whether or not the Qods Force was ordered from the top echelons of government.

"But my point is what's worse - them ordering it and it happening, or them not ordering it and it happening?

His comments came after the chair of the US Joint Chiefs of Staff, Marine General Peter Pace, cast doubt on the allegation the highest levels of Iran's Government were directing the weapons flows.

Marine General Pace told Voice of America radio the explosives were made in Iran.

"What I would not say is that the Iranian Government, per se, knows about this," he said.

General Pace's apparent break with the briefing in Baghdad added fuel to criticisms that the Bush Administration was exaggerating the case against Iran and recalled the bitter debate over the flawed case for invading Iraq.

"The idea that somehow we're manufacturing the idea that the Iranians are providing IEDs is preposterous," Mr Bush said.

"When we find the networks that are enabling these weapons to end up in Iraq, we will deal with them. If we find agents who are moving these devices into Iraq, we will deal with them."

The US President spoke hours after the US military in Baghdad formally repeated the charges made at the weekend briefing, where officials spoke on condition that they not be named and recording devices were banned.

Major General William Caldwell repeated the bulk of the charges but backtracked from Sunday's claim that the shipments were initiated at "the highest level" of the Iranian Government, calling that an analysts' inference.